Field of the Invention
The present invention relates generally to the field of fiber optics, and in particular to improved multifiber connectors for multicore optical fiber cables.
Background Art
The ever increasing demand for high-density, high-speed parallel optical data links, for super-computer and data-center applications, has spawned significant interest in passive optical devices designed to facilitate reliable, cost-effective deployment. In multi-channel parallel links for super computers and data centers, thousands of optical links, operating at 1 Gb/s to 10 Gb/s, may be utilized.
In conventional configurations, one-dimensional parallel optical links typically utilize a 1×12 multimode linear array of fibers, with each fiber serving as a separate channel. In this arrangement, the fibers, which are typically on a 250-μm pitch within a ribbon, are terminated into a molded multifiber ferrule, such as an MT ferrule. The MT-terminated fibers are then used to make connections between multi-channel VSCEL and PiN photodetector arrays. For applications requiring a more rugged assembly, jacketed fibers, typically in a ribbon configuration, are terminated within MT ferrules that are then placed inside MT-RJ, MPO, MTP™, or MPX Connector Housings, to produce robust patch cords.
MT ferrules are available in numerous sizes with various hole counts, to address a wide range of connector and signal routing applications. For example, the mini MT2 and mini MT4 are used in MT-RJ patch cords. The MT4, MT8, and MT12 are used in one-dimensional array MPO and MPX patch cords.
For even higher densities, manufacturers terminate fibers into 2D-array MT16, MT24, MT48, MT60, or MT72 ferrules. However, high-density configurations assembled using standard single-core fibers have proven to be extremely expensive to produce, since achieving physical contact between all of the fibers, when two connectors are mated, requires very precise control of the polishing process to ensure coplanarity (especially in the 72-fiber variant). Also, the molded MT ferrules are very expensive to produce. The production yields on 2D-array MT ferrules leads to significantly higher cost, as one hole out of position causes a ferrule to be rejected. For instance, if a 72-fiber ferrule has one hole that doesn't meet positional requirements, then the ferrule is discarded even though there are 71 correctly positioned holes.
In addition, stacking fiber ribbons to produce the ribbon cordages, needed for the 2D configurations, leads to a relatively large, bulky, and expensive package. Also, the flexibility of the ribbon cordage is adversely affected.